The route serves as a train-bus service of the portion of the Barrie line from East Gwillimbury GO Station to Aurora GO Station during off-peak and counter-peak hours when the train line is out of service, connecting East Gwillimbury, Newmarket and Aurora to downtown Toronto.
Weekday service is provided primarily by route 65, operating from East Gwillimbury GO Station to the Union Station Bus Terminal, making stops at the Newmarket Bus Terminal, Aurora GO Station and the Aurora/Highway 404 Carpool. During peak hours, additional buses may stop at the Newmarket GO Station instead of Aurora GO Station.
Note that all buses serve the Newmarket GO Station from bus stops on Davis Drive, as opposed to a bus terminal on site. East Gwillimbury GO Station is serviced Monday to Friday only.